orrelation with clinical and radiologic observations should establish or refute the concept of hydroxyapatite crystal-induced synovitis. Dicalcium phosphate dihydrate will be sought as part of this study. The total amount, concentration, and types of collagen found in joint fluid sediment will be correlated with the type of arthritis, synovial fluid oxygen partial pressure, clinical, radiologic and serologic parameters to explore its diagnostic, prognostic and pathogenetic significance.